AbstractThe objective of this study was to investigate through a nutritional and biochemical approach the variability of reproductive performance in dairy cows of semi arid area herds. Seventy four multiparous females reared in four farms were tracked from one month before calving to the third month postpartum. Information about reproductive events were taken once a month, and the body condition score evaluated on a 1 to 5 scale according to the EDMONSON method (1989). Blood samples were taken on a sample of 23 cows chosen according to body condition score before calving for biochemical analysis of energy, nitrogen and minerals parameters. Maximum concentrations depended to physiological stage. Blood glucose and calcium are stable at around 0.60g / l and 0.76 g / l respectively (p>0.05). Uremia (0.27g/l vs 0.16g/l) and triglycerides (0.74g/l vs 0.48g/l) are higher in the first month of lactation (p